When setting up to make a Gas Tungsten Arc (GTA) weld on low carbon steel, the following steps should be considered:
1. Preparation of the Tungsten Electrode: Low carbon steel requires specific electrode preparation to ensure proper weld quality.
- Shape: For low carbon steel welding, it is important to use a tungsten electrode that is pointed. A pointed electrode provides a concentrated and stable arc that is effective for the required precision in low carbon steel welding.
2. Polarity: The polarity setting on the welding machine is also crucial:
- DCEN (Direct Current Electrode Negative): For low carbon steel, DCEN is typically used. This means the electrode is connected to the negative terminal, allowing deeper penetration with a stable arc and minimal electrode overheating.
Therefore, the correct setup involves using a pointed tungsten electrode and setting the welding machine to DCEN.
Given these considerations, the correct answer to the question is:
a. pointed, DCEN
